I upgraded to a new Mac Mini Intel and asked for a serial swap for my new computer. I got that reasonably soon. Then I tried to find an option to insert that new serial number. Did not work, the programme told me, I'm already registered. After a few days I got response after filing a new question on their website. They told me to use the uninstaller and then install again. So I did, but it still said I'm registered with my unique ID code, so no picture! I asked for a way to be able to insert the new serial. No response. Meanwhile I got Leopard and upgraded. Now my Logitech Quick Cam Zoom is not recognised at all! No response from IOXperts.... Still it worked fine for the time beeing on my old G4 Mini.
It might be time just to buy a "Vista"-supported camera, they seem to be recognised by OSX out-of-the-box, still it's a shame IOXperts is so lax in helping me out...